To evaluate whether postoperative PROM scores of spine patients are influenced by memory bias

Inclusion Criteria:

• All adult patients with valid preoperative PROM scores submitted to spine surgery due to degenerative pathology from January 2019 to April 2020 at our center (spine unit of a neurosurgical department in a Portuguese university hospital) were included in the study and received PROMs questionnaires with a letter of consent.

Exclusion Criteria:

• Patients without valid preoperative questionnaires were excluded from the study while patients were lost to follow-up if mail questionnaires were not completed two months after PROMs remittance or if they had submitted incomplete or invalid answers.

patients are unaware whether they are in the intervention or control group